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><DIV
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><H1
CLASS="TITLE"
><A
NAME="AEN2"
>Video for Linux Two API Specification</A
></H1
><H2
CLASS="SUBTITLE"
>Revision 0.24</H2
><H3
CLASS="AUTHOR"
><A
NAME="AEN6"
></A
>Michael H Schimek</H3
><DIV
CLASS="AFFILIATION"
><DIV
CLASS="ADDRESS"
><P
CLASS="ADDRESS"
>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<CODE
CLASS="EMAIL"
>&#60;<A
HREF="mailto:mschimek@gmx.at"
>mschimek@gmx.at</A
>&#62;</CODE
><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P
></DIV
></DIV
><H3
CLASS="AUTHOR"
><A
NAME="AEN13"
></A
>Bill Dirks</H3
><H3
CLASS="AUTHOR"
><A
NAME="AEN17"
></A
>Hans Verkuil</H3
><H3
CLASS="AUTHOR"
><A
NAME="AEN21"
></A
>Martin Rubli</H3
><P
CLASS="COPYRIGHT"
>Copyright &copy; 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin
Rubli</P
><DIV
CLASS="LEGALNOTICE"
><P
></P
><A
NAME="AEN37"
></A
><P
>This document is copyrighted &copy; 1999-2008 by Bill
Dirks, Michael H. Schimek, Hans Verkuil and Martin Rubli.</P
><P
>Permission is granted to copy, distribute and/or modify
this document under the terms of the GNU Free Documentation License,
Version 1.1 or any later version published by the Free Software
Foundation; with no Invariant Sections, with no Front-Cover Texts, and
with no Back-Cover Texts. A copy of the license is included in the
appendix entitled "GNU Free Documentation License".</P
><P
>Programming examples can be used and distributed without
restrictions.</P
><P
></P
></DIV
><HR></DIV
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="f163.htm"
>Introduction</A
></DT
><DT
>1. <A
HREF="c174.htm"
>Common API Elements</A
></DT
><DD
><DL
><DT
>1.1. <A
HREF="c174.htm#OPEN"
>Opening and Closing Devices</A
></DT
><DD
><DL
><DT
>1.1.1. <A
HREF="c174.htm#AEN194"
>Device Naming</A
></DT
><DT
>1.1.2. <A
HREF="c174.htm#RELATED"
>Related Devices</A
></DT
><DT
>1.1.3. <A
HREF="c174.htm#AEN249"
>Multiple Opens</A
></DT
><DT
>1.1.4. <A
HREF="c174.htm#AEN270"
>Shared Data Streams</A
></DT
><DT
>1.1.5. <A
HREF="c174.htm#AEN273"
>Functions</A
></DT
></DL
></DD
><DT
>1.2. <A
HREF="x282.htm"
>Querying Capabilities</A
></DT
><DT
>1.3. <A
HREF="x294.htm"
>Application Priority</A
></DT
><DT
>1.4. <A
HREF="x309.htm"
>Video Inputs and Outputs</A
></DT
><DT
>1.5. <A
HREF="x341.htm"
>Audio Inputs and Outputs</A
></DT
><DT
>1.6. <A
HREF="x394.htm"
>Tuners and Modulators</A
></DT
><DD
><DL
><DT
>1.6.1. <A
HREF="x394.htm#AEN396"
>Tuners</A
></DT
><DT
>1.6.2. <A
HREF="x394.htm#AEN418"
>Modulators</A
></DT
><DT
>1.6.3. <A
HREF="x394.htm#AEN437"
>Radio Frequency</A
></DT
><DT
>1.6.4. <A
HREF="x394.htm#AEN445"
>Satellite Receivers</A
></DT
></DL
></DD
><DT
>1.7. <A
HREF="x448.htm"
>Video Standards</A
></DT
><DT
>1.8. <A
HREF="x542.htm"
>User Controls</A
></DT
><DT
>1.9. <A
HREF="x802.htm"
>Extended Controls</A
></DT
><DD
><DL
><DT
>1.9.1. <A
HREF="x802.htm#AEN804"
>Introduction</A
></DT
><DT
>1.9.2. <A
HREF="x802.htm#AEN809"
>The Extended Control API</A
></DT
><DT
>1.9.3. <A
HREF="x802.htm#AEN840"
>Enumerating Extended Controls</A
></DT
><DT
>1.9.4. <A
HREF="x802.htm#AEN867"
>Creating Control Panels</A
></DT
><DT
>1.9.5. <A
HREF="x802.htm#MPEG-CONTROLS"
>MPEG Control Reference</A
></DT
><DT
>1.9.6. <A
HREF="x802.htm#CAMERA-CONTROLS"
>Camera Control Reference</A
></DT
></DL
></DD
><DT
>1.10. <A
HREF="x1859.htm"
>Data Formats</A
></DT
><DD
><DL
><DT
>1.10.1. <A
HREF="x1859.htm#AEN1861"
>Data Format Negotiation</A
></DT
><DT
>1.10.2. <A
HREF="x1859.htm#AEN1894"
>Image Format Enumeration</A
></DT
></DL
></DD
><DT
>1.11. <A
HREF="x1904.htm"
>Image Cropping, Insertion and Scaling</A
></DT
><DD
><DL
><DT
>1.11.1. <A
HREF="x1904.htm#AEN1926"
>Cropping Structures</A
></DT
><DT
>1.11.2. <A
HREF="x1904.htm#AEN1954"
>Scaling Adjustments</A
></DT
><DT
>1.11.3. <A
HREF="x1904.htm#AEN1969"
>Examples</A
></DT
></DL
></DD
><DT
>1.12. <A
HREF="x2009.htm"
>Streaming Parameters</A
></DT
></DL
></DD
><DT
>2. <A
HREF="c2030.htm"
>Image Formats</A
></DT
><DD
><DL
><DT
>2.1. <A
HREF="c2030.htm#AEN2113"
>Standard Image Formats</A
></DT
><DT
>2.2. <A
HREF="x2123.htm"
>Colorspaces</A
></DT
><DT
>2.3. <A
HREF="x2428.htm"
>Indexed Format</A
></DT
><DT
>2.4. <A
HREF="x2490.htm"
>RGB Formats</A
></DT
><DD
><DL
><DT
><A
HREF="r2492.htm"
>Packed RGB formats</A
>&nbsp;--&nbsp;Packed RGB formats</DT
><DT
><A
HREF="r3735.htm"
>V4L2_PIX_FMT_SBGGR8 ('BA81')</A
>&nbsp;--&nbsp;Bayer RGB format</DT
><DT
><A
HREF="r3796.htm"
>V4L2_PIX_FMT_SBGGR16 ('BA82')</A
>&nbsp;--&nbsp;Bayer RGB format</DT
></DL
></DD
><DT
>2.5. <A
HREF="x3891.htm"
>YUV Formats</A
></DT
><DD
><DL
><DT
><A
HREF="r3896.htm"
>Packed YUV formats</A
>&nbsp;--&nbsp;Packed YUV formats</DT
><DT
><A
HREF="r4185.htm"
>V4L2_PIX_FMT_GREY ('GREY')</A
>&nbsp;--&nbsp;Grey-scale image</DT
><DT
><A
HREF="r4246.htm"
>V4L2_PIX_FMT_Y16 ('Y16 ')</A
>&nbsp;--&nbsp;Grey-scale image</DT
><DT
><A
HREF="r4339.htm"
>V4L2_PIX_FMT_YUYV ('YUYV')</A
>&nbsp;--&nbsp;Packed format with &frac12; horizontal chroma
resolution, also known as YUV 4:2:2</DT
><DT
><A
HREF="r4484.htm"
>V4L2_PIX_FMT_UYVY ('UYVY')</A
>&nbsp;--&nbsp;Variation of
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUYV</CODE
> with different order of samples
in memory</DT
><DT
><A
HREF="r4629.htm"
>V4L2_PIX_FMT_Y41P ('Y41P')</A
>&nbsp;--&nbsp;Format with &frac14; horizontal chroma
resolution, also known as YUV 4:1:1</DT
><DT
><A
HREF="r4850.htm"
>V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12')</A
>&nbsp;--&nbsp;Planar formats with &frac12; horizontal and
vertical chroma resolution, also known as YUV 4:2:0</DT
><DT
><A
HREF="r5016.htm"
>V4L2_PIX_FMT_YVU410 ('YVU9'), V4L2_PIX_FMT_YUV410 ('YUV9')</A
>&nbsp;--&nbsp;Planar formats with &frac14; horizontal and
vertical chroma resolution, also known as YUV 4:1:0</DT
><DT
><A
HREF="r5154.htm"
>V4L2_PIX_FMT_YUV422P ('422P')</A
>&nbsp;--&nbsp;Format with &frac12; horizontal chroma resolution,
also known as YUV 4:2:2. Planar layout as opposed to
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUYV</CODE
></DT
><DT
><A
HREF="r5319.htm"
>V4L2_PIX_FMT_YUV411P ('411P')</A
>&nbsp;--&nbsp;Format with &frac14; horizontal chroma resolution,
also known as YUV 4:1:1. Planar layout as opposed to
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_Y41P</CODE
></DT
><DT
><A
HREF="r5470.htm"
>V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</A
>&nbsp;--&nbsp;Formats with &frac12; horizontal and vertical
chroma resolution, also known as YUV 4:2:0. One luminance and one
chrominance plane with alternating chroma samples as opposed to
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU420</CODE
></DT
></DL
></DD
><DT
>2.6. <A
HREF="x5634.htm"
>Compressed Formats</A
></DT
><DT
>2.7. <A
HREF="x5665.htm"
>Reserved Format Identifiers</A
></DT
></DL
></DD
><DT
>3. <A
HREF="c5742.htm"
>Input/Output</A
></DT
><DD
><DL
><DT
>3.1. <A
HREF="c5742.htm#RW"
>Read/Write</A
></DT
><DT
>3.2. <A
HREF="x5791.htm"
>Streaming I/O (Memory Mapping)</A
></DT
><DT
>3.3. <A
HREF="x5884.htm"
>Streaming I/O (User Pointers)</A
></DT
><DT
>3.4. <A
HREF="x5950.htm"
>Asynchronous I/O</A
></DT
><DT
>3.5. <A
HREF="x5953.htm"
>Buffers</A
></DT
><DD
><DL
><DT
>3.5.1. <A
HREF="x5953.htm#AEN6266"
>Timecodes</A
></DT
></DL
></DD
><DT
>3.6. <A
HREF="x6386.htm"
>Field Order</A
></DT
></DL
></DD
><DT
>4. <A
HREF="c6488.htm"
>Interfaces</A
></DT
><DD
><DL
><DT
>4.1. <A
HREF="c6488.htm#CAPTURE"
>Video Capture Interface</A
></DT
><DD
><DL
><DT
>4.1.1. <A
HREF="c6488.htm#AEN6498"
>Querying Capabilities</A
></DT
><DT
>4.1.2. <A
HREF="c6488.htm#AEN6510"
>Supplemental Functions</A
></DT
><DT
>4.1.3. <A
HREF="c6488.htm#AEN6520"
>Image Format Negotiation</A
></DT
><DT
>4.1.4. <A
HREF="c6488.htm#AEN6563"
>Reading Images</A
></DT
></DL
></DD
><DT
>4.2. <A
HREF="x6570.htm"
>Video Overlay Interface</A
></DT
><DD
><DL
><DT
>4.2.1. <A
HREF="x6570.htm#AEN6587"
>Querying Capabilities</A
></DT
><DT
>4.2.2. <A
HREF="x6570.htm#AEN6595"
>Supplemental Functions</A
></DT
><DT
>4.2.3. <A
HREF="x6570.htm#AEN6605"
>Setup</A
></DT
><DT
>4.2.4. <A
HREF="x6570.htm#AEN6635"
>Overlay Window</A
></DT
><DT
>4.2.5. <A
HREF="x6570.htm#AEN6826"
>Enabling Overlay</A
></DT
></DL
></DD
><DT
>4.3. <A
HREF="x6831.htm"
>Video Output Interface</A
></DT
><DD
><DL
><DT
>4.3.1. <A
HREF="x6831.htm#AEN6839"
>Querying Capabilities</A
></DT
><DT
>4.3.2. <A
HREF="x6831.htm#AEN6849"
>Supplemental Functions</A
></DT
><DT
>4.3.3. <A
HREF="x6831.htm#AEN6859"
>Image Format Negotiation</A
></DT
><DT
>4.3.4. <A
HREF="x6831.htm#AEN6902"
>Writing Images</A
></DT
></DL
></DD
><DT
>4.4. <A
HREF="x6909.htm"
>Video Output Overlay Interface</A
></DT
><DD
><DL
><DT
>4.4.1. <A
HREF="x6909.htm#AEN6923"
>Querying Capabilities</A
></DT
><DT
>4.4.2. <A
HREF="x6909.htm#AEN6932"
>Framebuffer</A
></DT
><DT
>4.4.3. <A
HREF="x6909.htm#AEN6953"
>Overlay Window and Scaling</A
></DT
><DT
>4.4.4. <A
HREF="x6909.htm#AEN6987"
>Enabling Overlay</A
></DT
></DL
></DD
><DT
>4.5. <A
HREF="x6991.htm"
>Codec Interface</A
></DT
><DT
>4.6. <A
HREF="x7002.htm"
>Effect Devices Interface</A
></DT
><DT
>4.7. <A
HREF="x7013.htm"
>Raw VBI Data Interface</A
></DT
><DD
><DL
><DT
>4.7.1. <A
HREF="x7013.htm#AEN7029"
>Querying Capabilities</A
></DT
><DT
>4.7.2. <A
HREF="x7013.htm#AEN7038"
>Supplemental Functions</A
></DT
><DT
>4.7.3. <A
HREF="x7013.htm#AEN7045"
>Raw VBI Format Negotiation</A
></DT
><DT
>4.7.4. <A
HREF="x7013.htm#AEN7218"
>Reading and writing VBI images</A
></DT
></DL
></DD
><DT
>4.8. <A
HREF="x7236.htm"
>Sliced VBI Data Interface</A
></DT
><DD
><DL
><DT
>4.8.1. <A
HREF="x7236.htm#AEN7248"
>Querying Capabilities</A
></DT
><DT
>4.8.2. <A
HREF="x7236.htm#AEN7258"
>Supplemental Functions</A
></DT
><DT
>4.8.3. <A
HREF="x7236.htm#AEN7265"
>Sliced VBI Format Negotiation</A
></DT
><DT
>4.8.4. <A
HREF="x7236.htm#AEN7483"
>Reading and writing sliced VBI data</A
></DT
></DL
></DD
><DT
>4.9. <A
HREF="x7561.htm"
>Teletext Interface</A
></DT
><DT
>4.10. <A
HREF="x7578.htm"
>Radio Interface</A
></DT
><DD
><DL
><DT
>4.10.1. <A
HREF="x7578.htm#AEN7585"
>Querying Capabilities</A
></DT
><DT
>4.10.2. <A
HREF="x7578.htm#AEN7594"
>Supplemental Functions</A
></DT
><DT
>4.10.3. <A
HREF="x7578.htm#AEN7600"
>Programming</A
></DT
></DL
></DD
><DT
>4.11. <A
HREF="x7607.htm"
>RDS Interface</A
></DT
></DL
></DD
><DT
>I. <A
HREF="r7624.htm"
>Function Reference</A
></DT
><DD
><DL
><DT
><A
HREF="r7626.htm"
>V4L2 close()</A
>&nbsp;--&nbsp;Close a V4L2 device</DT
><DT
><A
HREF="r7667.htm"
>V4L2 ioctl()</A
>&nbsp;--&nbsp;Program a V4L2 device</DT
><DT
><A
HREF="r7771.htm"
>ioctl VIDIOC_CROPCAP</A
>&nbsp;--&nbsp;Information about the video cropping and scaling abilities</DT
><DT
><A
HREF="r7900.htm"
>ioctl VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</A
>&nbsp;--&nbsp;Read or write hardware registers</DT
><DT
><A
HREF="r8087.htm"
>ioctl VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD</A
>&nbsp;--&nbsp;Execute an encoder command</DT
><DT
><A
HREF="r8242.htm"
>ioctl VIDIOC_ENUMAUDIO</A
>&nbsp;--&nbsp;Enumerate audio inputs</DT
><DT
><A
HREF="r8304.htm"
>ioctl VIDIOC_ENUMAUDOUT</A
>&nbsp;--&nbsp;Enumerate audio outputs</DT
><DT
><A
HREF="r8367.htm"
>ioctl VIDIOC_ENUM_FMT</A
>&nbsp;--&nbsp;Enumerate image formats</DT
><DT
><A
HREF="r8494.htm"
>ioctl VIDIOC_ENUM_FRAMESIZES</A
>&nbsp;--&nbsp;Enumerate frame sizes</DT
><DT
><A
HREF="r8724.htm"
>ioctl VIDIOC_ENUM_FRAMEINTERVALS</A
>&nbsp;--&nbsp;Enumerate frame intervals</DT
><DT
><A
HREF="r8936.htm"
>ioctl VIDIOC_ENUMINPUT</A
>&nbsp;--&nbsp;Enumerate video inputs</DT
><DT
><A
HREF="r9149.htm"
>ioctl VIDIOC_ENUMOUTPUT</A
>&nbsp;--&nbsp;Enumerate video outputs</DT
><DT
><A
HREF="r9288.htm"
>ioctl VIDIOC_ENUMSTD</A
>&nbsp;--&nbsp;Enumerate supported video standards</DT
><DT
><A
HREF="r9539.htm"
>ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO</A
>&nbsp;--&nbsp;Query or select the current audio input and its
attributes</DT
><DT
><A
HREF="r9688.htm"
>ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</A
>&nbsp;--&nbsp;Query or select the current audio output</DT
><DT
><A
HREF="r9804.htm"
>ioctl VIDIOC_G_CHIP_IDENT</A
>&nbsp;--&nbsp;Identify the chips on a TV card</DT
><DT
><A
HREF="r9994.htm"
>ioctl VIDIOC_G_CROP, VIDIOC_S_CROP</A
>&nbsp;--&nbsp;Get or set the current cropping rectangle</DT
><DT
><A
HREF="r10104.htm"
>ioctl VIDIOC_G_CTRL, VIDIOC_S_CTRL</A
>&nbsp;--&nbsp;Get or set the value of a control</DT
><DT
><A
HREF="r10211.htm"
>ioctl VIDIOC_G_ENC_INDEX</A
>&nbsp;--&nbsp;Get meta data about a compressed video stream</DT
><DT
><A
HREF="r10386.htm"
>ioctl VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS,
VIDIOC_TRY_EXT_CTRLS</A
>&nbsp;--&nbsp;Get or set the value of several controls, try control
values</DT
><DT
><A
HREF="r10595.htm"
>ioctl VIDIOC_G_FBUF, VIDIOC_S_FBUF</A
>&nbsp;--&nbsp;Get or set frame buffer overlay parameters</DT
><DT
><A
HREF="r10944.htm"
>ioctl VIDIOC_G_FMT, VIDIOC_S_FMT,
VIDIOC_TRY_FMT</A
>&nbsp;--&nbsp;Get or set the data format, try a format</DT
><DT
><A
HREF="r11094.htm"
>ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</A
>&nbsp;--&nbsp;Get or set tuner or modulator radio
frequency</DT
><DT
><A
HREF="r11217.htm"
>ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</A
>&nbsp;--&nbsp;Query or select the current video input</DT
><DT
><A
HREF="r11285.htm"
>ioctl VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP</A
>&nbsp;--&nbsp;</DT
><DT
><A
HREF="r11430.htm"
>ioctl VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR</A
>&nbsp;--&nbsp;Get or set modulator attributes</DT
><DT
><A
HREF="r11612.htm"
>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</A
>&nbsp;--&nbsp;Query or select the current video output</DT
><DT
><A
HREF="r11680.htm"
>ioctl VIDIOC_G_PARM, VIDIOC_S_PARM</A
>&nbsp;--&nbsp;Get or set streaming parameters</DT
><DT
><A
HREF="r11946.htm"
>ioctl VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY</A
>&nbsp;--&nbsp;Query or request the access priority associated with a
file descriptor</DT
><DT
><A
HREF="r12051.htm"
>ioctl VIDIOC_G_SLICED_VBI_CAP</A
>&nbsp;--&nbsp;Query sliced VBI capabilities</DT
><DT
><A
HREF="r12265.htm"
>ioctl VIDIOC_G_STD, VIDIOC_S_STD</A
>&nbsp;--&nbsp;Query or select the video standard of the current input</DT
><DT
><A
HREF="r12342.htm"
>ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER</A
>&nbsp;--&nbsp;Get or set tuner attributes</DT
><DT
><A
HREF="r12784.htm"
>ioctl VIDIOC_LOG_STATUS</A
>&nbsp;--&nbsp;Log driver status information</DT
><DT
><A
HREF="r12816.htm"
>ioctl VIDIOC_OVERLAY</A
>&nbsp;--&nbsp;Start or stop video overlay</DT
><DT
><A
HREF="r12878.htm"
>ioctl VIDIOC_QBUF, VIDIOC_DQBUF</A
>&nbsp;--&nbsp;Exchange a buffer with the driver</DT
><DT
><A
HREF="r13022.htm"
>ioctl VIDIOC_QUERYBUF</A
>&nbsp;--&nbsp;Query the status of a buffer</DT
><DT
><A
HREF="r13105.htm"
>ioctl VIDIOC_QUERYCAP</A
>&nbsp;--&nbsp;Query device capabilities</DT
><DT
><A
HREF="r13317.htm"
>ioctl VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU</A
>&nbsp;--&nbsp;Enumerate controls and menu control items</DT
><DT
><A
HREF="r13641.htm"
>ioctl VIDIOC_QUERYSTD</A
>&nbsp;--&nbsp;Sense the video standard received by the current
input</DT
><DT
><A
HREF="r13696.htm"
>ioctl VIDIOC_REQBUFS</A
>&nbsp;--&nbsp;Initiate Memory Mapping or User Pointer I/O</DT
><DT
><A
HREF="r13817.htm"
>ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF</A
>&nbsp;--&nbsp;Start or stop streaming I/O</DT
><DT
><A
HREF="r13889.htm"
>V4L2 mmap()</A
>&nbsp;--&nbsp;Map device memory into application address space</DT
><DT
><A
HREF="r14037.htm"
>V4L2 munmap()</A
>&nbsp;--&nbsp;Unmap device memory</DT
><DT
><A
HREF="r14090.htm"
>V4L2 open()</A
>&nbsp;--&nbsp;Open a V4L2 device</DT
><DT
><A
HREF="r14169.htm"
>V4L2 poll()</A
>&nbsp;--&nbsp;Wait for some event on a file descriptor</DT
><DT
><A
HREF="r14264.htm"
>V4L2 read()</A
>&nbsp;--&nbsp;Read from a V4L2 device</DT
><DT
><A
HREF="r14390.htm"
>V4L2 select()</A
>&nbsp;--&nbsp;Synchronous I/O multiplexing</DT
><DT
><A
HREF="r14496.htm"
>V4L2 write()</A
>&nbsp;--&nbsp;Write to a V4L2 device</DT
></DL
></DD
><DT
>5. <A
HREF="c14592.htm"
>V4L2 Driver Programming</A
></DT
><DT
>6. <A
HREF="c14595.htm"
>Changes</A
></DT
><DD
><DL
><DT
>6.1. <A
HREF="c14595.htm#DIFF-V4L"
>Differences between V4L and V4L2</A
></DT
><DD
><DL
><DT
>6.1.1. <A
HREF="c14595.htm#AEN14602"
>Opening and Closing Devices</A
></DT
><DT
>6.1.2. <A
HREF="c14595.htm#AEN14665"
>Querying Capabilities</A
></DT
><DT
>6.1.3. <A
HREF="c14595.htm#AEN14821"
>Video Sources</A
></DT
><DT
>6.1.4. <A
HREF="c14595.htm#AEN14877"
>Tuning</A
></DT
><DT
>6.1.5. <A
HREF="c14595.htm#V4L-IMAGE-PROPERTIES"
>Image Properties</A
></DT
><DT
>6.1.6. <A
HREF="c14595.htm#AEN15120"
>Audio</A
></DT
><DT
>6.1.7. <A
HREF="c14595.htm#AEN15205"
>Frame Buffer Overlay</A
></DT
><DT
>6.1.8. <A
HREF="c14595.htm#AEN15269"
>Cropping</A
></DT
><DT
>6.1.9. <A
HREF="c14595.htm#AEN15302"
>Reading Images, Memory Mapping</A
></DT
><DT
>6.1.10. <A
HREF="c14595.htm#AEN15385"
>Reading Raw VBI Data</A
></DT
><DT
>6.1.11. <A
HREF="c14595.htm#AEN15438"
>Miscellaneous</A
></DT
></DL
></DD
><DT
>6.2. <A
HREF="x15446.htm"
>Changes of the V4L2 API</A
></DT
><DD
><DL
><DT
>6.2.1. <A
HREF="x15446.htm#AEN15449"
>Early Versions</A
></DT
><DT
>6.2.2. <A
HREF="x15446.htm#AEN15499"
>V4L2 Version 0.16 1999-01-31</A
></DT
><DT
>6.2.3. <A
HREF="x15446.htm#AEN15502"
>V4L2 Version 0.18 1999-03-16</A
></DT
><DT
>6.2.4. <A
HREF="x15446.htm#AEN15505"
>V4L2 Version 0.19 1999-06-05</A
></DT
><DT
>6.2.5. <A
HREF="x15446.htm#AEN15514"
>V4L2 Version 0.20 (1999-09-10)</A
></DT
><DT
>6.2.6. <A
HREF="x15446.htm#AEN15575"
>V4L2 Version 0.20 incremental changes</A
></DT
><DT
>6.2.7. <A
HREF="x15446.htm#AEN15628"
>V4L2 Version 0.20 2000-11-23</A
></DT
><DT
>6.2.8. <A
HREF="x15446.htm#AEN15657"
>V4L2 Version 0.20 2002-07-25</A
></DT
><DT
>6.2.9. <A
HREF="x15446.htm#AEN15660"
>V4L2 in Linux 2.5.46, 2002-10</A
></DT
><DT
>6.2.10. <A
HREF="x15446.htm#AEN16046"
>V4L2 2003-06-19</A
></DT
><DT
>6.2.11. <A
HREF="x15446.htm#AEN16089"
>V4L2 2003-11-05</A
></DT
><DT
>6.2.12. <A
HREF="x15446.htm#AEN16131"
>V4L2 in Linux 2.6.6, 2004-05-09</A
></DT
><DT
>6.2.13. <A
HREF="x15446.htm#AEN16139"
>V4L2 in Linux 2.6.8</A
></DT
><DT
>6.2.14. <A
HREF="x15446.htm#AEN16149"
>V4L2 spec erratum 2004-08-01</A
></DT
><DT
>6.2.15. <A
HREF="x15446.htm#AEN16170"
>V4L2 in Linux 2.6.14</A
></DT
><DT
>6.2.16. <A
HREF="x15446.htm#AEN16176"
>V4L2 in Linux 2.6.15</A
></DT
><DT
>6.2.17. <A
HREF="x15446.htm#AEN16203"
>V4L2 spec erratum 2005-11-27</A
></DT
><DT
>6.2.18. <A
HREF="x15446.htm#AEN16212"
>V4L2 spec erratum 2006-01-10</A
></DT
><DT
>6.2.19. <A
HREF="x15446.htm#AEN16223"
>V4L2 spec erratum 2006-02-03</A
></DT
><DT
>6.2.20. <A
HREF="x15446.htm#AEN16231"
>V4L2 spec erratum 2006-02-04</A
></DT
><DT
>6.2.21. <A
HREF="x15446.htm#AEN16241"
>V4L2 in Linux 2.6.17</A
></DT
><DT
>6.2.22. <A
HREF="x15446.htm#AEN16261"
>V4L2 spec erratum 2006-09-23 (Draft 0.15)</A
></DT
><DT
>6.2.23. <A
HREF="x15446.htm#AEN16297"
>V4L2 in Linux 2.6.18</A
></DT
><DT
>6.2.24. <A
HREF="x15446.htm#AEN16319"
>V4L2 in Linux 2.6.19</A
></DT
><DT
>6.2.25. <A
HREF="x15446.htm#AEN16338"
>V4L2 spec erratum 2006-10-12 (Draft 0.17)</A
></DT
><DT
>6.2.26. <A
HREF="x15446.htm#AEN16345"
>V4L2 in Linux 2.6.21</A
></DT
><DT
>6.2.27. <A
HREF="x15446.htm#AEN16351"
>V4L2 in Linux 2.6.22</A
></DT
><DT
>6.2.28. <A
HREF="x15446.htm#AEN16378"
>V4L2 in Linux 2.6.24</A
></DT
><DT
>6.2.29. <A
HREF="x15446.htm#AEN16388"
>V4L2 in Linux 2.6.25</A
></DT
></DL
></DD
><DT
>6.3. <A
HREF="x16430.htm"
>Relation of V4L2 to other Linux multimedia APIs</A
></DT
><DD
><DL
><DT
>6.3.1. <A
HREF="x16430.htm#XVIDEO"
>X Video Extension</A
></DT
><DT
>6.3.2. <A
HREF="x16430.htm#AEN16446"
>Digital Video</A
></DT
><DT
>6.3.3. <A
HREF="x16430.htm#AEN16450"
>Audio Interfaces</A
></DT
></DL
></DD
><DT
>6.4. <A
HREF="x16453.htm"
>Experimental API Elements</A
></DT
><DT
>6.5. <A
HREF="x16497.htm"
>Obsolete API Elements</A
></DT
></DL
></DD
><DT
>A. <A
HREF="a16506.htm"
>Video For Linux Two Header File</A
></DT
><DT
>B. <A
HREF="a16706.htm"
>Video Capture Example</A
></DT
><DT
>C. <A
HREF="a16721.htm"
>GNU Free Documentation License</A
></DT
><DD
><DL
><DT
>C.1. <A
HREF="a16721.htm#FDL-PREAMBLE"
>0. PREAMBLE</A
></DT
><DT
>C.2. <A
HREF="x16743.htm"
>1. APPLICABILITY AND DEFINITIONS</A
></DT
><DT
>C.3. <A
HREF="x16769.htm"
>2. VERBATIM COPYING</A
></DT
><DT
>C.4. <A
HREF="x16775.htm"
>3. COPYING IN QUANTITY</A
></DT
><DT
>C.5. <A
HREF="x16788.htm"
>4. MODIFICATIONS</A
></DT
><DT
>C.6. <A
HREF="x16896.htm"
>5. COMBINING DOCUMENTS</A
></DT
><DT
>C.7. <A
HREF="x16910.htm"
>6. COLLECTIONS OF DOCUMENTS</A
></DT
><DT
>C.8. <A
HREF="x16915.htm"
>7. AGGREGATION WITH INDEPENDENT WORKS</A
></DT
><DT
>C.9. <A
HREF="x16923.htm"
>8. TRANSLATION</A
></DT
><DT
>C.10. <A
HREF="x16929.htm"
>9. TERMINATION</A
></DT
><DT
>C.11. <A
HREF="x16933.htm"
>10. FUTURE REVISIONS OF THIS LICENSE</A
></DT
><DT
>C.12. <A
HREF="x16941.htm"
>Addendum</A
></DT
></DL
></DD
><DT
><A
HREF="i16960.htm"
>List of Types</A
></DT
><DT
><A
HREF="b17127.htm"
>References</A
></DT
></DL
></DIV
><DIV
CLASS="LOT"
><DL
CLASS="LOT"
><DT
><B
>List of Figures</B
></DT
><DT
>1-1. <A
HREF="x1904.htm#CROP-SCALE"
>Image Cropping, Insertion and Scaling</A
></DT
><DT
>3-1. <A
HREF="x6386.htm#FIELDSEQ-TB"
>Field Order, Top Field First Transmitted</A
></DT
><DT
>3-2. <A
HREF="x6386.htm#FIELDSEQ-BT"
>Field Order, Bottom Field First Transmitted</A
></DT
><DT
>4-1. <A
HREF="x7013.htm#VBI-HSYNC"
>Line synchronization</A
></DT
><DT
>4-2. <A
HREF="x7013.htm#VBI-525"
>ITU-R 525 line numbering (M/NTSC and M/PAL)</A
></DT
><DT
>4-3. <A
HREF="x7013.htm#VBI-625"
>ITU-R 625 line numbering</A
></DT
></DL
></DIV
><DIV
CLASS="LOT"
><DL
CLASS="LOT"
><DT
><B
>List of Examples</B
></DT
><DT
>1-1. <A
HREF="x309.htm#AEN328"
>Information about the current video input</A
></DT
><DT
>1-2. <A
HREF="x309.htm#AEN336"
>Switching to the first video input</A
></DT
><DT
>1-3. <A
HREF="x341.htm#AEN382"
>Information about the current audio input</A
></DT
><DT
>1-4. <A
HREF="x341.htm#AEN388"
>Switching to the first audio input</A
></DT
><DT
>1-5. <A
HREF="x448.htm#AEN510"
>Information about the current video standard</A
></DT
><DT
>1-6. <A
HREF="x448.htm#AEN519"
>Listing the video standards supported by the current
input</A
></DT
><DT
>1-7. <A
HREF="x448.htm#AEN530"
>Selecting a new video standard</A
></DT
><DT
>1-8. <A
HREF="x542.htm#AEN778"
>Enumerating all controls</A
></DT
><DT
>1-9. <A
HREF="x542.htm#AEN789"
>Changing controls</A
></DT
><DT
>1-10. <A
HREF="x1904.htm#AEN1972"
>Resetting the cropping parameters</A
></DT
><DT
>1-11. <A
HREF="x1904.htm#AEN1983"
>Simple downscaling</A
></DT
><DT
>1-12. <A
HREF="x1904.htm#AEN1991"
>Selecting an output area</A
></DT
><DT
>1-13. <A
HREF="x1904.htm#AEN1996"
>Current scaling factor and pixel aspect</A
></DT
><DT
>2-1. <A
HREF="x2123.htm#AEN2217"
>ITU-R Rec. BT.601 color conversion</A
></DT
><DT
>2-1. <A
HREF="r2492.htm#AEN3061"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR24</CODE
> 4 &times; 4 pixel
image</A
></DT
><DT
>2-1. <A
HREF="r3735.htm#AEN3746"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_SBGGR8</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r3796.htm#AEN3809"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_SBGGR16</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4185.htm#AEN4196"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_GREY</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4246.htm#AEN4257"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_Y16</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4339.htm#AEN4351"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUYV</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4484.htm#AEN4496"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_UYVY</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4629.htm#AEN4645"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_Y41P</CODE
> 8 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r4850.htm#AEN4871"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU420</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r5016.htm#AEN5032"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU410</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r5154.htm#AEN5170"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV422P</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r5319.htm#AEN5337"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV411P</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>2-1. <A
HREF="r5470.htm#AEN5493"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_NV12</CODE
> 4 &times; 4
pixel image</A
></DT
><DT
>3-1. <A
HREF="x5791.htm#AEN5823"
>Mapping buffers</A
></DT
><DT
>3-2. <A
HREF="x5884.htm#AEN5899"
>Initiating streaming I/O with user pointers</A
></DT
><DT
>4-1. <A
HREF="x6909.htm#AEN6949"
>Finding a framebuffer device for OSD</A
></DT
></DL
></DIV
></DIV
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